New compositions containing taxane derivatives

ABSTRACT

Compositions containing taxane derivatives, consist of a solution of such derivative in a surfactant consisting of polysorbate, polyethelene glycol or hydrogenated castor oil. These compositions can be used to prepare perfusion solutions essentially free of ethanol.

The present invention relates to compositions and especiallypharmaceutical dosage forms containing therapeutic agents havingantitumour and antileukaemic activity. It relates more especially tocompositions suitable for injection containing taxane derivatives, suchas, in particular, taxol or one of its analogues or derivatives of theformula: ##STR1## in which R represents a hydrogen atom or an acetylradical and R₁ represents a tert-butoxycarbonylamino or benzoyloxyaminoradical. Of these derivatives, that in which R represents an acetylgroup and R₁ represents a benzoyloxyamino group or that in which Rrepresents a hydrogen atom and R₁ represents a tert-butoxycarbonylaminoradical are preferred. The first of these two compounds is better knownby the name of taxol, and the second is known by the name of Taxotere.

These products exhibit in vivo substantial activity against malignantrumours, which has enabled them to be studied in the treatment ofdiseases resistant to other anticancer therapies.

Unfortunately, these products possess such low solubility in water thatit has been necessary to prepare formulations for injection containingsurfactant and ethanol. Ethanol is the best solvent for dissolvingcompounds of formula (I).

For example, according to the publication by Rowinsky, Lorraine,Cazenave and Donehower which appeared in the Journal of the NationalCancer Institute, vol. 82, No. 15, pages 1247-1259 on 1st Aug. 1990, afirst solution, termed "stock solution", containing approximately 6mg/ml of taxol in a solvent mixture composed of:

50% by volume of ethanol

50% by volume of Cremophor EL,

is prepared. On injection, this solution is mixed with a perfusion fluidcontaining sodium chloride or dextrose (glucose). To obtain a mixturewhich is stable from both a physical standpoint and a chemicalstandpoint, the authors of this paper state that it is necessary tolimit the concentration of active principle in the perfusion solution toconcentrations of approximately 0.03 to 0.6 mg/ml (see abovepublication, page 1251, column 1, third paragraph).

Now, it is desirable to be able to inject sufficient doses of activeprinciple; to this end, clinicians would like to inject concentrationsof active principle of between approximately 0.3 and 1 mg/ml in theperfusion fluid; above these doses, anaphylactic shock phenomena whichare difficult to control, due in the main to the Cremophor, are seen(see the publication by Rowinsky, page 1250, second column, lastparagraph).

Still according to this publication, to obtain such concentrations(between 0.3 and 1 mg/ml), it is necessary to inject solutionscontaining, at the same time as the active principle, concentrations ofeach of the following compounds, ethanol and most especially Cremophor,of approximately 8 g per 100 ml of solution. Since the treatment oftenrequires the administration of high doses of active principle, and sincethe concentration of the active principle in the solution is relativelylow, the injection of a large volume has the effect of causing, inaddition to anaphylactic manifestations, manifestations of alcoholpoisoning during the treatment.

The present invention provides compositions that make it possible eitherto reduce the ethanol concentrations greatly, or to eliminate Cremophorand ethanol completely from the perfusions.

For this purpose, according to a first implementation of the presentinvention, a composition suitable for use as a stock solution isprepared, containing a compound of formula I as defined above dissolvedin a surfactant which may be a polysorbate, e.g. as marketed under thename "Tween", a polyoxyethylene glycol ester as marketed, e.g., underthe name "Emulphor", or an ester of polyethylene glycol and castor oilas marketed, e.g., under the name Cremophor, and virtually free fromethanol.

The stock solution may be prepared by dissolving the active principle inethanol, which is the best biocompatible solvent for the taxanederivatives, and then gradually adding the surfactant. Solutionscontaining 10 to 100 mg/ml of active principle in a mixture containingapproximately 50% of surfactant can be prepared in this manner. Theethanol is then completely, or almost completely, eliminated.

To prepare, according to the present invention, the solution having alow ethanol content, the taxane derivative is dissolved in ethanol, andthe surfactant, which enables micelles to be formed containing thetaxane derivative encapsulated in the surfactant after dilution in anaqueous medium, is then added. The ethanol contained in this solution isthen removed at least partially by evaporation under vacuum or by anyother suitable means.

According to a second method for preparing the stock solution, thetaxane derivative is dissolved directly in the surfactant. According toa preferred method, a solution of surfactant containing, in particular,1 to 2% of ethanol is prepared, and the taxane derivative is addedcontinuously to this solution with stirring, e.g. using a helicalgrinder or a centrifugal disintegrator. The presence of a small amountof ethanol provides several advantages: the medium possesses a lowerviscosity, and the wetting of the powder and the final filtration of thesolution are improved.

The stock solution, having a low ethanol content, preferably containsless than 5% of ethanol; still more preferably, it contains less than 2%of ethanol. This solution is stable and can contain up to 200 mg/ml,preferably up to 80 mg/ml, of active principle in the surfactant.

A stock solution of taxol possesses still more preferably aconcentration of between 6 and 20 mg/ml of active principle in thesurfactant. This solution can be mixed, in particular to provide a finalconcentration of between 0.1 and 1 mg per milliliter, with the perfusionfluid, which can be physiological saline or a glucose solution.Perfusions prepared from the above stock solutions having a low ethanolcontent contain still more preferably between 0.3 and 0.5 mg/ml of taxoland less than 1 ml/l of ethanol.

The taxol perfusion containing the active principle without ethanolpossesses a physical stability of between 8 and about one hundred hours.Physical stability is understood to wean that the solution does notexhibit any visible precipitation after 8 to 10 hours of storage at roomtemperature.

A stock solution of Taxotere preferably possesses a concentration ofbetween 20 and 80 mg/ml of active principle in the surfactant. Thissolution can be mixed, in particular to provide a final concentration ofbetween 0.1 and 0.5 mg per milliliter, with the perfusion fluid, whichcan be a physiological saline or a glucose solution. Perfusions preparedfrom the above stock solutions having a low ethanol content containstill more preferably between 0.1 and 0.3 mg/ml of Taxotere; theypreferably contain less than 15 ml/l of surfactant and less than 1 ml/lof ethanol.

The Taxotere perfusion containing the active principle without ethanolpossesses a physical stability which can reach several months.

The taxol or Taxotere perfusions may be injected into humans at apredetermined flow rate depending on the amount of active principle itis desired to inject. The anaphylactic shock phenomena which wereobserved with the solutions of the prior can be avoided with thesesolutions.

Thus, these perfusions have made it possible to reduce, relative to theprior art, the amount of surfactant injected into humans byapproximately 80% and the amount of ethanol by almost 100%.

The invention is illustrated by the following Examples.

COMPARATIVE EXAMPLE ACCORDING TO THE PRIOR ART

Taxol (0.180 g) is dissolved in ethanol (15 ml). The mixture is made tovolume with Cremophor to obtain a solution (30 ml) which contains taxol(6 mg/ml).

This solution is diluted in a 5% glucose perfusion solution in aproportion of 1 mg/ml; the perfusion solution contains 87.7 ml/l ofCremophor and 87.7 ml/l of ethanol. The perfusion solution is stable formore than 21 hours.

EXAMPLES 1-7

Taxotere (32 g) is dissolved in absolute ethanol (340 ml) andPolysorbate 80 (830 g) is then added. The ethanol is evaporated off in arotary evaporator at 30° C. at a pressure of 15 mmHg for 2 hours. Thesolution obtained is stable; it contains Taxotere (40 mg/ml).

After dilution in a 5% glucose perfusion solution at concentrations of0.1, 0.3 and 0.5 mg/ml, the stability of the solutions obtained isobserved.

The same method is reproduced using a solution containing Taxotere (60mg/ml).

The same test is reproduced using taxol solutions containing taxol (12and 20 mg/ml).

The results are shown in Table 1.

                                      TABLE 1                                     __________________________________________________________________________               Stock solution                                                                        Active principle                                                                      Surfactant in                                                                        Ethanol in                                  Product                                                                            Solvent                                                                             concentration                                                                         in the perfusion                                                                      the perfusion                                                                        the perfusion                                                                        Stability                            __________________________________________________________________________    taxol                                                                              Polysorbate                                                                         20 mg/ml                                                                                1 mg/ml                                                                             50 ml/l                                                                              <0.3                                                                              ml/l                                                                             >8 H                                 taxol                                                                              Polysorbate                                                                         20 mg/ml                                                                              0.3 mg/ml                                                                             15 ml/l                                                                              <0.09                                                                             ml/l                                                                             >24 H                                taxol                                                                              Polysorbate                                                                         12 mg/ml                                                                                1 mg/ml                                                                             83.3                                                                             ml/l                                                                              <0.5                                                                              ml/l                                                                             >48 H                                Taxotere                                                                           Polysorbate                                                                         40 mg/ml                                                                              0.5 mg/ml                                                                             11.6                                                                             ml/l                                                                              0.09                                                                              ml/l                                                                             8 H-23 H                             Taxotere                                                                           Polysorbate                                                                         40 mg/ml                                                                              0.3 mg/ml                                                                             6.9                                                                              ml/l                                                                              0.05                                                                              ml/l                                                                             8 H-23 H                             Taxotere                                                                           Polysorbate                                                                         40 mg/ml                                                                              0.1 mg/ml                                                                             2.3                                                                              ml/l                                                                              0.02                                                                              ml/l                                                                             29 H-45 H                            Taxotere                                                                           Polysorbate                                                                         60 mg/ml                                                                              0.1 mg/ml                                                                             1.5                                                                              ml/l                                                                              <0.01                                                                             ml/l                                                                             8 H-23 H                             __________________________________________________________________________

EXAMPLE 8

Into a stainless steel reactor, Taxotere (258 g) is introduced anddissolved in ethanol (2425 g) with mechanical stirring for 45 minutes.Polysorbate 80 (6156 g) is added and the mixture is homogenised withmechanical stirring for 15 minutes. The solution is transferred to areactor and the alcohol is distilled off under a reduced pressure of 10to 50 millibars (1000 to 5000 Pa), the temperature being maintained atbetween 18° and 28° C. The alcohol is distilled off until its content isless than 2%.

The solution obtained is filtered through a filter having a pore size of0.2 μm. It contains:

ethanol (1.3% )

Taxotere (39.6 mg/ml).

After dilution to 1 mg/ml in a perfusion bag containing 5% glucose, thesolution is stable without apparent precipitation for a period of morethan 2 months.

EXAMPLE 9

Taxotere (160 mg) or taxol (160 mg) is dissolved in a mixture (10 ml) ofabsolute ethanol (2 ml) and Cremophor EL(218) (8 ml), and the ethanol isevaporated off in a rotary evaporator at 30° C. at a pressure of 25 mmhgfor 3 hours. The solutions obtained are stable. They contain 20 mg/ml ofTaxotere or taxol. After dilution in a 5% glucose perfusion solution atconcentrations of 0.1 and 0.5 mg/ml, precipitation is observed atbetween 30 and 95 hours.

EXAMPLE 10

Polysorbate 80 (275.5 g) and absolute ethanol (5.4 g) are placed in a500-ml Erlenmeyer flask, and the mixture is then stirred with a barmagnet until completely homogenised.

The solution prepared above (26.13 g) in a 50 ml flask, placed in awater bath heated beforehand and maintained throughout the test periodat 30° C., is stirred at approximately 600 rpm with a bar magnet. With aspatula, Taxotere (1.076 g) is added in several portions so that theclumps disappear between two additions (the duration of the operation isapproximately one hour). After incorporation of the last fraction ofTaxotere, stirring is maintained until the solution becomes clear(approximately two hours).

We claim:
 1. A composition consisting essentially of a compound offormula: ##STR2## in which R represents a hydrogen atom or an acetylradical and R₁ represents a tert-butoxycarbonylamino or benzoylaminoradical, dissolved in a surfactant selected from the group consisting ofpolysorbate, polyoxyethylene glycol and hydrogenated castor oil, andessentially free of ethanol.
 2. A composition according to claim 1,which contains less than 5% by volume of ethanol.
 3. A compositionaccording to claim 1, wherein, in the compound of formula (I), Rrepresents hydrogen and R₁ represents a tert-butoxycarbonylaminoradical.
 4. A composition according to claim 1, wherein, in the compoundof formula (I), R represents an acetyl group and R₁ represents abenzoyloxyamino radical.
 5. A composition according to claim 1, whichcontains up to 200 mg/ml of compound of formula (I).
 6. A compositionaccording to claim 3, which contains 20 to 80 mg/ml of compound offormula (I).
 7. A composition according to claim 4, which contains 6 to20 mg/ml of compound of formula (I).
 8. A composition according to claim2, wherein the composition contains less than 2% of ethanol.
 9. Acomposition according to claim 5, which contains up to 80 mg/ml ofcompound of formula (I).
 10. Composition consisting essentially of ataxane derivative of the formula: ##STR3## in which R represents ahydrogen atom or an acetyl radical and R₁ represents atert-butoxycarbonylamino or benzoylamino radical dissolved in asurfactant selected from the group consisting of polysorbate,polyoxyethylene glycol and hydrogenated castor oil, said compositioncontaining less than 5% by volume ethanol.
 11. Composition according toclaim 10, wherein ethanol is less than 2% by volume.
 12. A perfusioncomprising less than 0.5 mg/ml of compound as defined in claim 3 andless than 1 ml/l of ethanol and less than 15 ml/l of surfactant.
 13. Aperfusion, comprising 1 mg/ml or less of compound as defined in claim 4and less than 1 ml/l of ethanol.
 14. A perfusion according to claim 12,wherein the perfusion contains 0.1 to 0.3 mg/ml of a compound of formula(I) wherein R represents hydrogen and R₁ represents atert-butoxycarbonylamino radical.
 15. A method for preparing acomposition according to claim 1, which comprises dissolving a compoundof formula (I) in ethanol, adding the surfactant and removing theethanol.
 16. A method for preparing a composition according to claim 1,which comprises slowly adding a compound of formula (I) to a solution ofthe surfactant containing 1 to 2% by volume of ethanol.
 17. A method forpreparing a composition according to claim 15, wherein ethanol isremoved by evaporation.